The present disclosure broadly relates to air suspension systems and, more particularly, to an electronically controlled air suspension system for use in association with a stationary vehicle that adjusts the air springs of the stationary vehicle to vary the height of the vehicle chassis.
The present disclosure finds particular application in association with the use of larger mobile vehicles, such as cargo vehicles, recreational vehicles (RVs), travel trailers and over-the-road truck trailers, for example, and will be described herein with particular reference thereto. However, it is to be understood that such vehicles are simply exemplary structures and that the present disclosure is capable of broader application in association with the height adjustment of a wide variety of structures and vehicles. Further examples of such structures and vehicles include gun platforms, military and civilian personnel transport vehicles, and ambulances.
Many larger vehicles, such as cargo vehicles, RVs, travel trailers, over-the-road truck trailers and the like, have an air suspension system for regulating the height of the vehicle chassis relative to the supporting axles, in a manner that is dependent upon the load placed in the vehicle, to adjust the height of the chassis in response to the ride conditions experienced by the vehicle. In addition, as in the case of cargo vehicles, the height of the vehicle chassis may be adjusted by an operator to suit a variety of loading platforms at different heights. These suspension systems usually consist of a plurality of fluid suspension members, such as air springs, which support the vehicle chassis above the axles. The height of the air springs is controlled by the ingress and egress of pressurized fluid from a suitable source mounted on the vehicle, such as a compressor. One or more intervening valves are traditionally used to facilitate the ingress and egress of pressurized fluid respectively into and out of the air springs, thus adjusting the height of the air springs and correspondingly the position of the vehicle chassis relative to the vehicle axles. Such systems also enable the vehicle chassis to be maintained in an orientation substantially aligned with the axles while the vehicle is stationary. This is accomplished by individually regulating the heights of the air springs that support the vehicle chassis on the axles. To control the height of the vehicle chassis, the operator/driver usually activates a switch to adjust the chassis height to a predetermined height, such as the approximate loading platform height.
One disadvantage associated with the mere adjustment of the chassis height to a predetermined height is the circumstance where a loading platform height is not equivalent to the predetermined height. This scenario produces a vehicle chassis height which is above or below the loading platform height and produces a step which must be traversed to load and unload the vehicle.
This disclosure provides a means for incrementally adjusting the height of a chassis after a preselected height has been achieved. By incrementally/decrementally adjusting the chassis height, more accurate alignment of a loading platform and vehicle chassis can be achieved.